Quartz rock

Silicon makes up 25.7% of the earth s crust, by weight, and is the second most abundant element, being exceeded only by oxygen. Silicon is not found free in nature, but occurs chiefly as the oxide and as silicates. Sand, quartz, rock crystal, amethyst, agate, flint, jasper, and opal are some of the forms in which the oxide appears. Granite, hornblende, asbestos, feldspar, clay, mica, etc. are but a few of the numerous silicate minerals. 

Quarz-faden, m. quartz thread, quartz filament, -fels, m. quartz rock, quartzite, -fenster, n. quartz window, quarzfrei, a. free from quartz. 

The composition of the particles is related to that of the source rocks. Quartz sand [composed of silica (silicon dioxide)], which makes up the most common variety of silica sand, is derived from quartz rocks. Pure quartz is usually almost free of impurities and therefore almost colorless (white). The coloration of some silica sand is due to chemical impurities within the structure of the quartz. The common buff, brown, or gray, for example, is caused by small amounts of metallic oxides iron oxide makes the sand buff or brown, whereas manganese dioxide makes it gray. Other minerals that often also occur as sand are calcite, feldspar and obsidian Calcite (composed of calcium carbonate), is generally derived from weathered limestone or broken shells or coral feldspar is an igneous rock of complex composition, and obsidian is a natural glass derived from the lava erupting from volcanoes see Chapter 2. 

Dr. Kellogg, who approved the condemnation on March 30. Among the items discarded from the Hall collection were "minerals," "shot," "cross bar ," "quartzite," "iron pyrites," and "quartz rock," as well as "pebbles," "sand stone rock," "one lot sea shells," "drift wood," "plumbago used by natives," and "rib of spotted seal."... 

Silicon dioxide (SiO ) is the most abundant compound in the Earths crust. Known as common sand, it also exists in the forms of quartz, rock crystal, amethyst, agate, flint, jasper, and opal. It has many industrial uses. 

Silicon is also a silicate and the earth s crust is made of complex silicates containing—Si O Si O linkage. Silica (Si02) occurs in nature in many forms such as quartz, rock, crystal sand, sound stone, flint, etc. 

Historically, fused quartz referred to transparent products produced from quartz crystal rock, and fused silica referred to opaque products produced from sand. With the advent of new manufacturing techniques, transparent products can now be produced from sand, so the old distinction is no longer applicable. Currently, the term fused quartz is used whenever the raw product is either quartz rock or sand. The term fused silica is used whenever the raw product is synthetically derived (from SiCl4). Generically, the term quartz glass or, better yet, vitreous silica can be used to cover the whole range of materials. 

Quartz Rock crystal Rhinestone Colorless, translucent to transparent Usually as terminated hexagonal prisms sometimes massive... 

Tectosilicate Quartz family Quartz (rock crystal) Si02... 

Some speculations on the nature of high-angle grain boundaries in quartz rocks. In Mineral and Rock Deformation Laboratory Studies, The Paterson... 

Inorganic salts, which contain metal ions, do not dissolve in organic solvents such as benzene. However, by surrounding the metal ion with a chelate called a crown ether the desired solution can be made. The mining industry uses cyanide ions to dissolve gold out of the quartz rocks in which it is often found. The cyanide ligands are removed in subsequent chemical steps. 

SYNONYMS agate, alpha-quartz, amethyst, crystallized silieon dioxide, flint, onyx, quartz, rock crystal, rose quartz, sand, silica dust, silica flour (powdered crystalline silica), tiger-eye. 

The effluent from the saturator, consisting of a solution of aluminum chloride in the charging stock, was discharged to the top of the reactor. The reactor was packed in some instances with 0.6-cm. semiporcelain Berl saddles, in others with 3-8 mesh quartz rock chips. 

Stn. Silica.—This acid is found pure in rock crystal, or in white quartz. Along vrith small and variable quantities of certain metallic oxides it forms many well-known minerals—as yellow or smoke rock crystal with oxide of iron agate, jasper, heliotrope, camelian, with the same metal amethyst with oxide of manganese prase with oxide of nickel rose-quartz with some fugitive colouring matter opal and calcedony with water, c. c. Many sands and sandstones are nearly pure silica, and quartz rock and flint are quite pure. 

Crystallography is the branch of the exact sciences that studies the structure of matter on an atomic scale the determination, classification and interpretation of the geometrical structures of solids and, in particular, those of crystals. A crystal is a solid whose microscopic structure is characterized by a periodic repetition in three dimensions of a motif composed of atoms. In the case of quartz (rock crystal), for example, the motif is made up of three silicon atoms and six oxygen atoms and occupies a volume of 113 (0.113 nm ). Thus crystals have ordered... 

Specifically, there is no indication of the presence of a significant amount of either clay minerals or organic matter. Thus all our conclusions obtained on bulk samples apparently apply to chert as a pure, monomineralic quartz rock. 

The reservoir rock consists primarily of unconsolidated fine to medium grained, litharenites with quartz, rock fragments, feldspars and clay minerals. Sands are moderately to well sorted with good intergranular porosity. These immature sands are slightly compacted to uncompacted, and cores tend to explode after retrieval due to the trapped gas. The clay minerals which constitute 5% - 7% of the rock are kaolinite, chlorite and illite. Clays also occur as aggregates. 

Crystalline silicas are used where a coarse, high-wear finish is desirable. However, they are abrasive. These materials are used mostly in thermosets and highly specialized thermoplastics. Available types include screen grades, quartzite sand, sandstone, quartz rock, and novaculite. 

Vitric tuff Pyroclastic Perlitic texture. Composed manily quartz, rock fragments and plagioclase that are the within the vitreous groundmass... 

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